HISTORY OF THE ATOMIC THEORY. 131 



never occurs to them that hot air is air and heat, and that moist 

 air is air and moisture, but they are qualities put on by air at 

 will, or at command, by accident, by growth, by motion, or 

 by life. The qualities of the elements are not substantial 

 forms, but accidents; the original first matter forms the 

 elements which put on various forms, and so perform everything 

 that elements have the power of accomplishing. The changes 

 are performed by generation, fermentation, and corruption. 



Baume, a believer in the four elements and phlogiston, 

 in 1773, says, that it is of no advantage to consult the 

 ancient chemists, they are so ambiguous ; and says : * — 



" Is it not probable that nature combines the elements in a 

 direct manner by twos and twos, and by threes and threes, by 

 means absolutely unknown to us ? If these simple combinations 

 exist, they will be secondary principles, or principles made 

 from principles (principes principles), of which nature makes 

 use to form compound bodies. Knowledge, on this subject, 

 entirely fails. We have no information on the immediate 

 combinations of the four elements ; we only know that they 

 have such a disposition to mix, that it is impossible to have 

 them perfectly pure and isolated from each other." 



We have here an opinion freed from the shackles of salt and 

 sulphur, but not beyond the early times, and I think not so 

 penetrating, although as practical as Roger Bacon's. 



It will be interesting here to quote Bishop Watson, 

 a man who brought into chemistry more common sense 

 and less pretension than many less penetrating observers. 

 Speaking of elements, he says, ** by chemical elements, 

 which are the last products of chemical analysis, we are to 

 understand, not very minute indivisible particles of matter, 

 but the simple homegeneal parts of bodies which are not 

 capable, as far as our experience teaches us, of any farther 

 resolution or division, except in a mechanical sense, into 



• Page 1 10, Vol. I., of" Chymie Experimentnlc ct Raisonn6e." 



